The objective of this research is to determine to what extent the ratio of oxidized to reduce pyridine nucleotides (NAD/NADH), intramitochondrial oxaloacetate concentration, and tissue adenosine triphosphate concentration are important to the regulation of renal metabolism during changes in systemic acid-base balance. These factors will be assessed in renal cortical tissue from Holtzman rats in normal acid-base balance, chronic metabolic acidosis, chronic metabolic alkalosis, and during potassium depletion; and in dogs after acute respiratory and metabolic alkalosis. The influence of these factors on renal metabolism and especially renal citrate metabolism can then be assessed. This information will add to our understanding of changes in renal metabolism which occur during systemic acid-base alterations.